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Challenging the Broken-Window theory

How can we prevent individuals from urinating in open areas?

In the Nudge TV show “The Power of Habit”, Sille Krukow, a behavioural expert based in Denmark, designed a nudge to help the Copenhagen Central Station. The problem they were faced with was that many men would urinate in hidden corners outside the building, despite the close location of public (and clean) toilets.


Staff has to clean the area several times a day

According to Ms. Krukow, this phenomenon can be explained by the broken-window theory of policing (Wilson and Kelling, 1982). When individuals observe others misbehaving, they tend to act in the same way, instead of doing the right thing.

The solution adopted in the show was to add a urinal to the area in question and stickers on the sidewalks signaling the direction and distance to the closest WC.

WC stickers.png

Implementation of the WC stickers


Urinal installed in the most critical zone

Around 500 people had been observed urinating in two corners of the station during the week before the experiment. After the intervention, half of the people did the right thing, i.e. they instantly used the urinal, while the other half started  to urinate on the street, but changed their behaviour once they saw the urinal. This means that the cleaning staff and station customers were saved of 5,000 liters of urine a week!

To learn more about this nudge (and other experiments), you can find the episodes online here.

By bbiasblog

The official blog of B.BIAS - Bocconi Behavioural Insights Associations of Students

4 replies on “Challenging the Broken-Window theory”

Dear Alison, in my humble opinion, the Broken-Window Theory is related to the dirtiness of those areas. In the TV show, the Central Station director says that, despite their efforts, there are budget and personnel limitations that prevent them to keep those areas clean all day long. When one individual sees that the region is disordered, he will not respect it either, analogously to the metaphor of the “broken windows”. This starts a sequence of bad behaviors that will “define” the area as a dirty one, where one “could” urinate without being reprehended. That is why the solutions proposed would be a challenge to the BWT. What’s your view on this?


Broken Window refers to the opportunity, that causes “bad” behavior ( see it as a negative nudge) . That does not mean, that you cannot remedy this behavior through measures, that come from a different angle.


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